The Michigan Left

[Flo]

Ole Lomarre asked me a questions yesterday after I had left about the Michigan left. I wasn't around and so I figured I'd make a post about it.

The Michigan Left, sometimes called the median U-turn, or thrU-turn intersection, is simply another type of intersection. It is notable because it essentially eliminates traditional left turns. Simply put, you cannot turn left at most intersections on a road like this. These types of intersections are common in Detroit, where they are best known for, but are often found all over Michigan. Highland Rd (M-59) near where I am from also uses this style of intersection.



The beauty of this is you never have to cross significant lanes of traffic. At the intersection you either go straight or right -- that's it. If you want to go left, you make a right turn and then perform a u-turn at the next crossing, which are usually right by major intersections, as you'll see below. Smaller intersections do not have full intersections, typically, and to get on the road you will have to simply turn right and then perform the u-turn to move in the other direction.



Not everyone likes these intersections, for whatever reason. When used appropriately, they often save time at the intersection. Oddly enough, if you are lucky, you can sometimes actually make a left turn faster than you could go straight through the interesection, if you turn right on the red (something you can do sometimes) and then u-turn and move straight through the intersection. 

To me, these are just another type of intersection. Once you know how to use them, they aren't that bad. You can always tell a new person to Michigan because they think they are the weirdest thing in the world. I've only seen someone attempt a left at one of these intersections two or three times, and one of the times it caused an accident. These aren't only Michigan features, however. If you go to the wikipedia page you'll see they have been implemented in other parts of the country and world, but not with the prevalence you would find in Pure Michigan.

Anyway, I hope you enjoyed your brief lesson on the Michigan Left.



source: https://en.wikipedia.org/wiki/Michigan_left

[DeSchaine]

Depending on traffic, these can either be great, or be the MOST ANNOYING THING IN THE WORLD. Especially the ones on Telegraph.

[Seperallis]

This is actually incredibly interesting and not something I even knew existed. I wish you could make something like this in Cities:SL

[Flo]

You can, if you use one way roads effectively and don't have stoplights at the U-turns. I'm not sure you could in vanilla, but using mods I'm certain its possible.

I agree about the ones on telegraph lol.

I drove on 12 mile about a month ago and it made me realize just how useful they are. Ton of traffic but everyone got where they were going. On M-59 there just isn't a lot of volume so it always seemed wasteful. 12 Mile converted me lol

[Jamzor the Jaxxor]

Maybe I'm just dumb but I fail to see how these are any more effective than just turning left at the intersection. You still have to wait for the traffic and turn left, you just do it slightly further down the road.

[Sal]

It seems like the difficult part would be making the right turn and then immediately getting all the way to the far left lane to make the subsequent U turn on a two-or-more lane road during rush hour or on a busy road.

[Flo]

You would have to drive on it to see for yourself, but in general it's actually much quicker. The intersections involved (both the main intersection and the u-turns if they have lights) are all two-phase intersections, meaning there are only two "phases" the intersection uses. For a large intersection, you would typically need three or four phases, meaning the two usual ones as well as a "left hand turn phase". Furthermore, the lights are very easy to coordinate since they're all simply two phase systems.

I'm not doing a terribly good job of explaining this, but I hope that helped.

These types of intersections aren't necessarily about getting people where they want to go faster, but managing the flow better, so there aren't as many stoppages. It also reduces the number of collisions (left hand turns cause a large number, you'd be surprised) and also makes pedestrian travel easier, since they don't have to deal with left hand turns crossing their paths. You definitely have to travel more distance to make the left turn. I read something like an average of a half a mile? That being said, traffic flow is typically better.

Also the good thing about these roads is that, if you do miss the U-turn, there's always another just a bit down the road. It's also not terribly hard to get over. speeds aren't usually that crazy at the big roads in Detroit and especially the u-turns right by the intersection people know not to be in the left-hand lane since that's where the slow people are (since they're decelerating into the turn lane). Some that I've been on actually have a dedicated lane just for the u-turns.

[Seperallis]

You're not dumb, Jam. On low capacity and low traffic roads, this kind of scheme would be completely useless. Even on a high capacity road with low capacity cross streets, I'm not seeing the benefit over a traditional intersection.

However, this kind of scheme is rather ingenious at dealing with congestion at intersections between two high-capacity, high-traffic roads. For example, say we're at the intersection between a highway an a main city arterial street. At rush hour, you might sit through two, maybe even three (if shit's really bad) cycles at the light trying to turn left; this is because, as traffic backs up, it'll eventually back itself out of the left turn lane and into normal traffic, causing even more congestion as people going straight try to get over into the next lane. Then, even when that lane finally goes, you still have people trying to turn left stuck way back in line, who get up to the light right as they lose their signal (I see this here in Columbia A LOT). Eliminating the traditional left (lel) and using this style gets rid of that kind of congestion, reducing commute times.

Furthermore, the "Michigan Left" completely does away with an entire traffic cycle. No longer do cars traveling straight have to deal with sitting at a red light, waiting for a few cars to turn left. There are two signals only: East-West travel, & North-South travel. Cutting the left turn lanes in all 4 directions nearly halves the time it takes to get through a signal pattern on these heavy multi-lane roads; you can now choose to either get through the signal pattern twice as fast, or keep the same pattern length and get twice as many cars through the intersection.

It's a pretty ingenious solution to common traffic problems, assuming the conditions are right for it. I disagree with Sal; I feel this actually works best on busy roads, where Jam's scenario of "going out of your way" essentially doesn't exist, given the circumstances.

It all comes down to the knowledge of the traffic engineer, using his 4+ years of schooling, bazillion certifications & decades of experience to know when to use this thing, and mitigate its problems. It's not intended to be an end-all solution to every traffic problem, but just one more tool to solve certain specific ones.

Also, I just noticed Flo posted while I was pecking away on my phone, but fuq it, I'm not editing this.

[Flo]

yeah, pretty much hit the nail on the head lol.

The one by where I live, M-59, is almost too much, but I could see in certain places (M-59 Highland and US-16 Grand River) how having to deal with the left turn would just make the intersection take forever.

In busy cities though, these are dope. I agree

[DeSchaine]

Except that in the past couple of years, MDOT has started to move towards more roundabouts. We have two in Kalamazoo, they're putting in a third, Mattawan has two and one on M-43 between Kalamazoo and South Haven. Problem is, no one around here knows how to use them yet so they have caused more problems than they solved.